CN109309240B

CN109309240B - Direct ethanol fuel cell and preparation method thereof

Info

Publication number: CN109309240B
Application number: CN201811160895.XA
Authority: CN
Inventors: 黄燕; 王稼奇
Original assignee: Shenzhen Graduate School Harbin Institute of Technology
Current assignee: Shenzhen Graduate School Harbin Institute of Technology
Priority date: 2018-09-30
Filing date: 2018-09-30
Publication date: 2020-09-11
Anticipated expiration: 2038-09-30
Also published as: CN109309240A

Abstract

The invention relates to the technical field of batteries, and discloses a preparation method of a direct ethanol fuel battery, which comprises the following steps: synthesizing a catalyst: mixing silicon dioxide powder, cane sugar and trithiocyanuric acid, preheating to obtain mixed powder, adding teflon and mixing with the mixed powder, and heating the mixture of the mixed powder and the teflon to obtain an N and S codoped carbon catalyst; synthesizing an electrolyte: adopting an initiator to carry out polymerization reaction on sodium acrylate, and soaking a hydrogel product obtained by the polymerization reaction in a strong alkali solution; preparing a cathode: coating the N, S co-doped carbon catalyst on a collector to obtain a cathode; preparing an anode: coating a Pt-Ru/C catalyst on a collector to obtain an anode; preparing a battery: and sandwiching the soaked hydrogel between the cathode and the anode to obtain the battery. The battery of the technical scheme has high flexibility and high capacity density, and has the function of being used immediately after dropping.

Description

Direct ethanol fuel cell and preparation method thereof

Technical Field

The invention relates to the technical field of batteries, in particular to a direct ethanol fuel battery and a preparation method thereof.

Background

A fuel cell is an energy conversion device that directly converts chemical energy of fuel into electrical energy, and the reaction process is essentially an oxidation-reduction reaction (ORR). The main components of the fuel cell are: an anode, a cathode, an electrolyte, and a current collector. The anode and cathode, in addition to conducting electrons, also act as catalysts for the redox reaction. Electrolytes fall into both acidic and alkaline categories, and some studies have shown that ethanol oxidizes at a much faster rate in alkaline environments than in acidic environments. The fuel cells can be classified into hydrogen fuel cells, methane fuel cells, methanol fuel cells and ethanol fuel cells according to the types of fuels, wherein the ethanol fuel cells are popular among people due to the characteristics of portability, no toxicity, low cost, easy storage and the like, and have wide application prospects.

However, to date, there is still no flexible Direct Ethanol Fuel Cell (DEFC) that can be used in practice, mainly because, on the one hand, existing catalysts are susceptible to deactivation by poisoning of ethanol catalytic oxidation intermediates (e.g., CO), and, on the other hand, existing electrolytes are susceptible to failure in a strongly alkaline environment.

Disclosure of Invention

The invention aims to provide a flexible and practical direct ethanol fuel cell and a preparation method of the direct ethanol fuel cell.

In one aspect, the present invention provides a method for preparing a direct ethanol fuel cell, comprising the following steps: synthesizing a catalyst: mixing silicon dioxide powder, cane sugar and trithiocyanuric acid, preheating to obtain mixed powder, adding teflon and mixing with the mixed powder, and heating the mixture of the mixed powder and the teflon to obtain an N and S codoped carbon catalyst; synthesizing an electrolyte: adopting an initiator to carry out polymerization reaction on sodium acrylate, and soaking a hydrogel product obtained by the polymerization reaction in a strong alkali solution; preparing a cathode: coating the N, S co-doped carbon catalyst on a collector to obtain a cathode; preparing an anode: coating a Pt-Ru/C catalyst on a collector to obtain an anode; preparing a battery: and sandwiching the soaked hydrogel between the cathode and the anode to obtain the battery.

Preferably, the silicon dioxide powder, the sucrose and the trithiocyanuric acid which are equal in mass are dispersed into deionized water, concentrated sulfuric acid is added and fully stirred, a mixed solution is obtained through ultrasonic treatment, and then the preheating step is carried out, wherein the weight of the concentrated sulfuric acid accounts for 3% -5% of the sum of the weight of the silicon dioxide powder, the weight of the sucrose and the weight of the trithiocyanuric acid.

Preferably, the preheating step comprises heating the mixed solution to 90-100 ℃ until the liquid is evaporated to obtain a solid, and heating the solid to 150-160 ℃ to obtain the mixed powder.

Preferably, the step of heating the mixture of the mixed powder and teflon comprises heating to 500-600 ℃ for 1-1.5 hours in an inert atmosphere environment, and then heating to 1000-1100 ℃ for 3-3.5 hours at a heating rate of 5-8 ℃/min, wherein the ratio of the weight of teflon to the weight of the silica powder is greater than or equal to 10, and the teflon is in a powder form.

Preferably, the synthesis step of the sodium acrylate comprises: fully stirring acrylic acid monomers and deionized water in a mass ratio of 8: 9-10 under an ice bath condition to obtain an acrylic acid solution, fully mixing sodium hydroxide and deionized water in a mass ratio of 1.5: 1-1.2 to obtain a sodium hydroxide solution, slowly adding the sodium hydroxide solution into the acrylic acid solution, wherein the mass ratio of the acrylic acid monomers to the sodium hydroxide is 2: 1-1.5, and completely neutralizing to obtain the sodium acrylate.

Preferably, the temperature of the polymerization reaction is 40 +/-3 ℃, the time of the polymerization reaction is 30-32 hours, the hydrogel product obtained by the polymerization reaction is dried at 100 ℃ for 1 hour and then soaked in the strong alkali solution, and the strong alkali solution is 3-5 mol/L potassium hydroxide solution.

Preferably, the step of preparing the cathode comprises: mixing a Nafion solution, isopropanol and deionized water in a mass ratio of 1: 1.8-2: 7-7.2 to obtain a mixed solution, dispersing the N and S co-doped carbon catalyst in the mixed solution to obtain first ink, and coating the first ink on the collector to obtain a cathode.

Preferably, the step of preparing the anode comprises: dispersing the Pt-Ru/C catalyst in the mixed solution to obtain second ink, and coating the second ink on the collector to obtain an anode, wherein the mass ratio of the Pt-Ru/C catalyst in the second ink to the N and S co-doped carbon catalyst in the first ink is 1: 2.

in another aspect, the invention also provides a direct ethanol fuel cell, which comprises a cathode, an anode and an electrolyte, wherein the electrolyte is sandwiched between the cathode and the anode, the cathode is prepared by coating an N, S co-doped carbon catalyst on a collector, the anode is prepared by coating a Pt-Ru/C catalyst on the collector, and the electrolyte is a sodium polyacrylate alkaline hydrogel electrolyte.

Preferably, the current collector is a carbon cloth covered with a sponge layer.

The direct ethanol fuel cell provided by the invention adopts the N and S CO-doped carbon catalyst to manufacture the cathode, the catalyst cannot be inactivated by poisoning of ethanol catalytic oxidation intermediate products (such as CO), the catalytic activity is high, the cost is low, and the synthesized N and S CO-doped carbon catalyst can be directly used for manufacturing the cathode without being used for subsequent treatment, so that the manufacturing process of the cell is effectively simplified. The sodium polyacrylate alkaline hydrogel is used as the electrolyte, has super-strong water absorption and water retention capacity, is compatible with strong alkali, has excellent ionic conductivity and durability, and effectively solves the problem that the electrolyte in the prior art is easy to lose efficacy in a strong alkaline environment. The battery manufactured by adopting the N, S co-doped carbon catalyst, the Pt-Ru/C catalyst and the sodium polyacrylate alkaline hydrogel electrolyte has excellent flexibility and high energy density, and can immediately supply power for an electronic clock, a smart phone and the like by only dripping ethanol when in use.

Drawings

Further features of the present invention will become more apparent from the following description of preferred embodiments thereof, which are provided by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of the synthesis of N, S co-doped carbon catalysts;

FIG. 2a shows TEM characterization results of N, S co-doped carbon catalyst;

FIG. 2b is an Electron Energy Loss Spectroscopy (EELS) spectrum of a doping element in the N, S co-doped carbon catalyst;

FIG. 3a is a comparison of electrocatalytic performance of N, S co-doped carbon catalysts in the presence of 1mol/L methanol and in the absence of methanol;

FIG. 3b is a polarization curve of N, S co-doped carbon catalyst in alkaline and acidic environments;

FIG. 3c is a CV curve of N, S co-doped carbon catalyst;

FIG. 4 is a schematic diagram of a synthetic sodium polyacrylate alkaline hydrogel electrolyte;

FIG. 5 is a graph of ionic conductivity over time for a sodium polyacrylate hydrogel film at 100% stretch;

FIG. 6 is a schematic illustration of making a cathode and an anode;

FIG. 7a shows the results of ethanol storage capacity tests on carbon cloth;

FIG. 7b shows the results of ethanol storage capacity test of sponge;

FIG. 8a is the TEM characterization of Pt-Ru/C catalyst;

FIG. 8b is an Electron Energy Loss Spectroscopy (EELS) spectrum of each element in the Pt-Ru/C catalyst;

FIG. 9a is a comparison of electrocatalytic performance of Pt-Ru/C catalysts with 1mol/L methanol and no methanol;

FIG. 9b is a polarization curve of Pt-Ru/C catalyst in alkaline and acidic environments;

FIG. 9C is a CV curve for the Pt-Ru/C catalyst;

FIG. 10a is a schematic diagram of the direct ethanol fuel cell of the present embodiment;

FIG. 10b is a schematic diagram of a direct ethanol fuel cell made in this example to power a smart phone;

FIG. 11 shows the results of electrochemical performance tests of the direct ethanol fuel cell prepared in this example;

fig. 12 shows the flexibility test of the direct ethanol fuel cell manufactured in this example.

Detailed Description

In order that the objects and advantages of the invention will be more clearly understood, the invention will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

First embodiment

The embodiment provides a direct ethanol fuel cell and a preparation method thereof.

The direct ethanol fuel cell comprises a cathode, an anode and electrolyte, wherein the electrolyte is clamped between the cathode and the anode, the cathode is prepared by coating N and S co-doped carbon catalyst on a collector, the anode is prepared by coating Pt-Ru/C catalyst on the collector, and the electrolyte is sodium polyacrylate alkaline hydrogel electrolyte.

In this embodiment, the method for preparing a direct ethanol fuel cell includes the following steps:

step 1: synthesis of N, S co-doped carbon catalyst by in-situ etching method

As shown in fig. 1, a schematic diagram of the synthesis of N, S co-doped carbon catalyst. Mixing silicon dioxide powder, cane sugar and trithiocyanuric acid, and preheating to obtain mixed powder; and then adding teflon and mixing with the mixed powder, and heating the mixture of the mixed powder and the teflon to obtain the N and S codoped carbon catalyst. In this embodiment, the silica powder, sucrose and trithiocyanuric acid are equal in mass, and the silica powder is preferably fumed silica (fumed silica) having a particle size of 200 nm. In this embodiment, firstly, silicon dioxide powder, sucrose and trithiocyanuric acid are dispersed into deionized water, then concentrated sulfuric acid is added and fully stirred, wherein the weight of the concentrated sulfuric acid accounts for 3% of the sum of the weight of the silicon dioxide powder, the weight of the sucrose and the weight of the trithiocyanuric acid, the mass fraction of the concentrated sulfuric acid is preferably 96% to 97%, and then ultrasonic treatment is performed for about 10min to obtain a mixed solution. And preheating the mixed solution to obtain the mixed powder, wherein in the embodiment, the preheating step comprises two steps: firstly, heating the mixed solution to 100 ℃ to evaporate liquid until the mixed solution becomes solid, and then heating the solid to 160 ℃ to polymerize the sucrose and crosslink the trithiocyanuric acid to obtain mixed powder. In this embodiment, the prepared mixed powder is first milled, then uniformly mixed with an excessive amount of teflon, and after mixing, the mixed powder is heated to 600 ℃ for 1 hour in an inert atmosphere environment, and then heated to 1100 ℃ at a heating rate of 5 ℃/min for 3 hours for pyrolysis to obtain N, S co-doped carbon catalyst powder. Preferably, the teflon is powder with a particle size of 5um, and the ratio of the weight of the teflon to the weight of the fumed silica powder is greater than or equal to 10.

In the pyrolysis process of heating the mixture of the mixed powder and the teflon to obtain the N, S codoped carbon catalyst, the silicon dioxide powder is directly etched away by HF generated by the reaction between tetrafluoroethylene (from the teflon) and water (from sucrose), i.e. the silicon dioxide reacts with the HF to generate SiF₄And volatilizes into the air, thereby avoiding any subsequent treatment and effectively simplifying the manufacturing process of the battery. The method is adopted to prepare the N, S codoped carbon catalystThe cost can be effectively reduced.

As shown in fig. 2a, the TEM representation result of the N, S co-doped carbon catalyst is shown, and the scale bar is 10 nm; as shown in fig. 2b, it is an Electron Energy Loss Spectrum (EELS) spectrum of the doping element in the N, S co-doped carbon catalyst, and its scale bar is 1 um. From fig. 2a, it can be easily seen that the layered pores of amorphous carbon are easily seen, and from fig. 2b, it can be seen that the doping elements N and S are uniformly distributed in the porous carbon skeleton, and since the porous structure of carbon and the uniform distribution of the doping elements greatly contribute to improving the activity of the catalyst, it can be seen that the N, S co-doped carbon catalyst prepared by the method has high catalytic activity.

As shown in fig. 3a, the electrocatalytic performance of N, S co-doped carbon catalyst was compared in the case of 1mol/L methanol and no methanol, where RHE represents the reversible hydrogen electrode. As can be seen from the figure, the presence and absence of methanol have no effect on the electrocatalytic performance of the N, S CO-doped carbon catalyst, and the methanol has very similar chemical and physical properties to ethanol, so that the effect of methanol on the N, S CO-doped carbon catalyst is equal to the effect of ethanol on the N, S CO-doped carbon catalyst, thereby verifying that the N, S CO-doped carbon catalyst is not deactivated by the poisoning effect of the ethanol catalytic oxidation intermediate (e.g., CO). As shown in fig. 3b, which is a polarization curve of the N, S co-doped carbon catalyst in alkaline and acidic environments, and as shown in fig. 3c, which is a CV curve of the N, S co-doped carbon catalyst, it can be seen that the N, S co-doped carbon catalyst shows higher electrocatalytic activity in alkaline environments compared to acidic environments.

Step 2: synthetic sodium polyacrylate alkaline hydrogel electrolyte

Fig. 4 is a schematic diagram of the synthesis of sodium polyacrylate alkaline hydrogel electrolyte. Adopting initiator to make sodium acrylate produce polymerization reaction, soaking the hydrogel product obtained by polymerization reaction in strong alkali solution. In this embodiment, the synthesis of sodium acrylate comprises: and (2) fully stirring 48g of acrylic acid monomer and 54g of deionized water under an ice bath condition to obtain an acrylic acid solution, fully mixing 26.7g of sodium hydroxide and 18g of deionized water to obtain a sodium hydroxide solution, slowly adding the sodium hydroxide solution into the acrylic acid solution, and completely neutralizing to obtain the sodium acrylate. In this example, the initiator is preferably 0.78g of Ammonium Persulfate (APS), the polymerization reaction is carried out in an oven at a temperature of 40 +/-3 ℃ for 30h, and the product sodium polyacrylate hydrogel (PANA) obtained by the polymerization reaction is firstly dried at 100 ℃ for 1 hour and then soaked in 5mol/L of potassium hydroxide solution.

As shown in fig. 5, the ionic conductivity of the sodium polyacrylate hydrogel film in a 100% stretched state is plotted against time. It can be seen from the figure that the conductivity of the sodium polyacrylate hydrogel film is substantially stabilized at about 0.24S/cm for 25 hours, which is two to three orders of magnitude higher than the ion conductivity of most polymer electrolytes in the prior art, even under severe 100% stretching conditions, and the sodium polyacrylate hydrogel film also successfully lights up the LED bulb. Therefore, the sodium polyacrylate hydrogel has super flexibility, stability and long-term stable ionic conductivity. And the sodium polyacrylate alkaline hydrogel has super water absorption and water retention capacity, is compatible with strong alkali, and can effectively avoid the problem that the electrolyte in the prior art is easy to lose efficacy in the strong alkaline environment.

And step 3: preparation of the cathode

As shown in fig. 6, the cathode is obtained by coating the N, S co-doped carbon catalyst (NSDC) prepared in step 1 on a collector, wherein the collector is preferably a gas-permeable carbon cloth, and as shown in fig. 7a, the result of the ethanol storage capacity test of the carbon cloth is shown, and it can be seen from the figure that the carbon cloth can absorb ethanol with the same mass as itself in a short time of 1S, which is much stronger than the ethanol absorption capacity of the collector such as CNT paper, metal mesh, etc. commonly used in the prior art. In this example, the specific method of coating employed the following steps: adding 0.1g of 5 wt.% Nafion solution into a mixed solution of 0.18g of isopropanol and 0.72g of deionized water, then dispersing 10mg of N and S co-doped carbon catalyst into the prepared mixed solution to obtain a first ink, preferably, ultrasonically dispersing for 15 minutes, and coating the first ink on the collector to obtain a cathode. In this example, the catalyst loading of the coated cathode was 2mg/cm²Coating area of 1cm². In this embodiment, theThe current collector is a carbon cloth covered with a sponge layer, and as shown in fig. 7b, the result of ethanol storage capacity test of the sponge is shown, and it can be seen from the figure that the sponge can absorb more ethanol in the same short time, and the ethanol absorption mass of the sponge can reach 33 times of the mass of the sponge within 1s, so that the carbon cloth covered with the sponge layer can greatly improve the ethanol absorption capacity of the current collector. By adopting the collector electrode in the embodiment, the long-time discharge of the ethanol fuel cell can be ensured.

And 4, step 4: preparation of the Anode

The anode is coated on the collector by a commercial Pt-Ru/C catalyst. In this example, the coating method is similar to that in step 3, and the Pt-Ru/C catalyst is dispersed in the prepared mixed solution by ultrasonic wave to obtain the second ink, and the second ink is coated on the collector to obtain the anode, where the coating area is 1cm²With the difference that the mass of the Pt-Ru/C catalyst was 5mg, resulting in a catalyst loading of 1mg/cm for the coated anode²。

As shown in FIG. 8a, the TEM representation result of the Pt-Ru/C catalyst is shown, the scale bar is 5nm, and the diameter of the nanoparticles in the graph is 3-7 nm; as shown in FIG. 8b, which is an Electron Energy Loss Spectrum (EELS) spectrum of each element in the Pt-Ru/C catalyst with a scale bar of 500nm, it can be seen that Pt and Ru are uniformly distributed on the carbon support, which makes the Pt-Ru/C catalyst have many active sites.

As shown in FIG. 9a, comparing the electrocatalytic performance of the Pt-Ru/C catalyst in the presence of 1mol/L methanol and in the absence of methanol, it can be seen that the Pt-Ru/C catalyst has outstanding alcohol oxidation performance, so that the oxidation of ethanol can be ensured by using the Pt-Ru/C catalyst as the anode of the cell in this embodiment. As shown in FIG. 9b, which is a polarization curve of the Pt-Ru/C catalyst in alkaline and acidic environments, and as shown in FIG. 9C, which is a CV curve of the Pt-Ru/C catalyst, it can be seen that the Pt-Ru/C catalyst shows higher oxidation performance in alkaline environments compared to acidic environments.

And 5: preparation of a Battery

And (3) sandwiching the hydrogel (namely the sodium polyacrylate alkaline hydrogel electrolyte) soaked in the step (2) between the cathode prepared in the step (3) and the anode prepared in the step (4), and then assembling the cathode, the electrolyte and the anode together through a fine wire and the like to obtain the Direct Ethanol Fuel Cell (DEFC). As shown in fig. 10a, the schematic diagram of the direct ethanol fuel cell manufactured by the embodiment is used, and power can be supplied to an electronic clock, a smart phone and the like immediately even if only ethanol is required to be added dropwise during use. Fig. 10b is a schematic diagram of a direct ethanol fuel cell manufactured by the present embodiment for supplying power to a smart phone. Therefore, the direct ethanol fuel cell prepared by the embodiment can be put into large-scale commercial application.

As shown in fig. 11, which shows the results of electrochemical performance tests (performed at room temperature and atmospheric pressure) of the direct ethanol fuel cell manufactured in this example, wherein a represents an OCV curve, it can be seen that the Open Circuit Voltage (OCV) of the cell in this example reaches a maximum of 1.14V and stabilizes above 0.73V, verifying that the cell in this example can be operated in high electrochemical kinetics. b shows the polarization curve and the corresponding power density calculation, from which it can be seen that the cell in this example achieves 21.48mW/cm²And is capable of operating over a wide range of current densities. c represents 0.1 to 1mA/cm²The discharge curve at each current density of (a) can be seen from the graph, and the battery of this example was 0.1mA/cm²The current density of the lithium ion battery can be continuously discharged for 21 hours, and only 3mL of ethanol is needed; even at 0.25mA/cm²、0.5mA/cm²、1mA/cm²Can be respectively and continuously discharged for 13.3h, 9.8h and 4.3h under the high current density. d represents 0.1 to 1mA/cm²As can be seen from the graph, when the current density is increased several times, the discharge voltage also maintains a high and stable state, which shows that the battery of the present embodiment can be well adapted to various currents. e represents the performance comparison between the direct ethanol fuel cell prepared by the embodiment and other high-performance cells in the prior art. As can be seen from the figure, it is related to PPy// MnO₂，LiCoO₂//Li，TiO₂//Li，LiCoO₂//Li₄Ti₅O₁₂，PANI//Li，LiMn₂O₄//Li₄Mn₅O₁₂，Ni(OH)₂Compared with high-performance batteries such as// Fe, NiCoO// Zn, PPy// Li and the like, the battery prepared by the embodiment has better performance, and reaches 1.41mWh/cm²The maximum area energy density of.

As shown in fig. 12, the flexibility test of the direct ethanol fuel cell manufactured by using the present example was performed. Where a represents a discharge curve continuously bent by 0 °, 30 °, 60 ° to 180 °, it can be seen that the discharge voltage decreases by only 0.06V as a whole from 0 ° to 180 °. b represents the discharge curves after various bending times, and it can be seen from the graph that the battery manufactured in this example maintains more than 68% of the initial voltage even after 1000 times of bending, and these results are sufficient to demonstrate that the battery of this example has excellent flexibility. C indicates that three flexible DEFC cells are connected in series to power the electronic clock, and it can be seen that even though the three cells are severely flexed, the three cells can be connected in series to power the electronic clock. D is the demonstration of three DEFC in series, namely the drop and play function, under the condition that ethanol is not dripped, the DEFC does not supply power, the electronic clock does not work, once the ethanol is dripped, the DEFC supplies power, the electronic clock works, and only a very small amount of ethanol is needed, so that the drop and play function which is not existed in the technical field of batteries before is realized.

Second embodiment

The same parts of this embodiment as those of the first embodiment are omitted here and will not be described again, and the differences are:

the weight of the concentrated sulfuric acid accounts for 5% of the sum of the weight of the silicon dioxide powder, the weight of the sucrose and the weight of the trithiocyanuric acid;

the preheating step comprises the steps of heating the mixed solution to 90 ℃ until the liquid is evaporated to obtain a solid, and heating the solid to 150 ℃ to obtain the mixed powder;

the step of heating the mixture of the mixed powder and the teflon comprises the steps of firstly heating to 500 ℃ for 1.5 hours under the inert atmosphere environment, then heating to 1000 ℃ for 3.5 hours, wherein the heating rate is 5 ℃/min;

fully stirring 48g of acrylic acid monomer and 60g of deionized water under an ice bath condition to obtain an acrylic acid solution, and fully mixing 27g of sodium hydroxide and 21g of deionized water to obtain a sodium hydroxide solution;

the polymerization reaction time is 32 hours, and a product obtained by the polymerization reaction is dried at 100 ℃ for 1 hour and then is soaked in the strong alkali solution, wherein the strong alkali solution is 3mol/L potassium hydroxide solution;

0.1g of a 5 wt.% Nafion solution, 0.2g of isopropyl alcohol and 0.7g of deionized water were mixed to obtain a mixed solution.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The preparation method of the direct ethanol fuel cell is characterized by comprising the following steps:

synthesizing a catalyst: mixing silicon dioxide powder, cane sugar and trithiocyanuric acid, preheating to obtain mixed powder, adding teflon and mixing with the mixed powder, and heating the mixture of the mixed powder and the teflon to obtain an N and S codoped carbon catalyst;

synthesizing an electrolyte: adopting an initiator to carry out polymerization reaction on sodium acrylate, and soaking a hydrogel product obtained by the polymerization reaction in a strong alkali solution;

preparing a cathode: coating the N, S co-doped carbon catalyst on a collector to obtain a cathode;

preparing an anode: coating a Pt-Ru/C catalyst on a collector to obtain an anode;

preparing a battery: and sandwiching the soaked hydrogel between the cathode and the anode to obtain the battery.

2. The preparation method according to claim 1, wherein the silicon dioxide powder, the sucrose and the trithiocyanuric acid with equal mass are dispersed into deionized water, concentrated sulfuric acid is added, the mixture is fully stirred and subjected to ultrasonic treatment to obtain a mixed solution, and then the preheating step is performed, wherein the weight of the concentrated sulfuric acid accounts for 3% -5% of the sum of the weight of the silicon dioxide powder, the weight of the sucrose and the weight of the trithiocyanuric acid.

3. The method according to claim 2, wherein the preheating step comprises heating the mixture to 90-100 ℃ until the liquid is evaporated to obtain a solid, and heating the solid to 150-160 ℃ to obtain the mixed powder.

4. The method according to any one of claims 1 to 3, wherein the step of heating the mixture of the mixed powder and Teflon comprises heating to 500-600 ℃ for 1-1.5 hours under an inert atmosphere, and then heating to 1000-1100 ℃ for 3-3.5 hours at a rate of 5-8 ℃/min, wherein the ratio of the weight of Teflon to the weight of the silicon dioxide powder is 10 or more, and Teflon is in a powder form.

5. The method according to any one of claims 1 to 3, wherein the step of synthesizing sodium acrylate comprises: fully stirring acrylic acid monomers and deionized water in a mass ratio of 8: 9-10 under an ice bath condition to obtain an acrylic acid solution, fully mixing sodium hydroxide and deionized water in a mass ratio of 1.5: 1-1.2 to obtain a sodium hydroxide solution, slowly adding the sodium hydroxide solution into the acrylic acid solution, wherein the mass ratio of the acrylic acid monomers to the sodium hydroxide is 2: 1-1.5, and completely neutralizing to obtain the sodium acrylate.

6. The preparation method of claim 5, wherein the temperature of the polymerization reaction is 40 ± 3 ℃, the time of the polymerization reaction is 30-32 hours, the hydrogel product obtained by the polymerization reaction is dried at 100 ℃ for 1 hour and then soaked in the strong alkali solution, and the strong alkali solution is 3-5 mol/L potassium hydroxide solution.

7. The production method according to any one of claims 1 to 3, wherein the step of producing a cathode comprises: mixing a Nafion solution, isopropanol and deionized water in a mass ratio of 1: 1.8-2: 7-7.2 to obtain a mixed solution, dispersing the N and S co-doped carbon catalyst in the mixed solution to obtain first ink, and coating the first ink on the collector to obtain a cathode.

8. The method of claim 7, wherein the step of preparing an anode comprises: dispersing the Pt-Ru/C catalyst in the mixed solution to obtain second ink, and coating the second ink on the collector to obtain an anode, wherein the mass ratio of the Pt-Ru/C catalyst in the second ink to the N and S co-doped carbon catalyst in the first ink is 1: 2.

9. the direct ethanol fuel cell comprises a cathode, an anode and electrolyte, wherein the electrolyte is clamped between the cathode and the anode, and the direct ethanol fuel cell is characterized in that the cathode is prepared by coating an N and S co-doped carbon catalyst on a collector, wherein the N and S co-doped carbon catalyst is prepared by preheating mixed powder of silicon dioxide powder, cane sugar and trithiocyanuric acid and then adding Teflon for mixing and heating, the anode is prepared by coating a Pt-Ru/C catalyst on the collector, and the electrolyte is sodium polyacrylate alkaline hydrogel electrolyte.

10. The direct ethanol fuel cell of claim 9 wherein the current collector is a carbon cloth covered with a sponge layer.